Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: marshall on December 17, 2009, 01:30:21 pm
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Hi all, new to this forum and cant seem to find the answer to my question, so apologies if its already been asked.
I have an arcade machine called 'operation thunderbolt' which has been working perfectly since I bought it in June, its kept in my garage and since the weather has changed, its a very cold garage.
Anyway I decided to switch the machine on to let it warm through incase it gets damp when I became aware that the monitor isnt displaying colors correctly. I left it on overnight with no improvement. The screen was very red, but now it seems more purple/blue. Ive adjusted the gain screws on the monitor board with no improvement. According to the manual its a Hantarex 9000 monitor.
So can anyone give me advice as to whats wrong?
Is it likely to be because its cold or more serious? Im in the UK so its a 240 volt with a transformer.
Thanks
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sounds like the degauss is not working,do the colours shift if you rotate the machine
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Thanks for the reply.
No nothing changes when the unit is moved, the screen is very blue/purple.
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got a photo?
sounds like the red drive transistor shorted and blew
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There is some discoloration down the side and bottom of the screen where its gone slightly yellow.
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looks like the red drive transistor is short circuit
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That doesnt sound good.
Is it likely to be because its damp/get better when its warmer, and easy to repair?
I can handle a soldering iron but do you know which transistor and the value?
I have the schematics but have no idea which one it is.
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http://wiki.arcadeotaku.com/index.php/Hantarex_Polo_1 (http://wiki.arcadeotaku.com/index.php/Hantarex_Polo_1)
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OK thanks for your help, I will change them and see what happens.
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remove T2 and T3 ,that will prove the fault
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Im a total novice with this, what should happen if I remove those transistors?
Im assuming that if they are faulty, there should be no difference in the picture?
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nah,if you remove the red drive transistor then you should lose all red,if the screen remains red the crt red gun is short
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Sorry, Im confused. I thought red had gone and replacing their transistors would restore it, the screen is very blue/purple.
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looks red to me from the photo
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I dont think the photo looks the same as it does when Im looking at the actual screen, but I think you know more than me so will just do as you said and change the transistors. I can change the red and if that doesnt work, change the others. What was it you said if that doesnt work, its the tube?
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i don't have the manual handy at the moment but the drive transistors are the ones with the heat sinc fins attached,they are a common fault on hantarex
you could swap them around and see if the colour problem changes
worst case scenario is crt,its unlikely but you can't rule it out
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Im so glad I found this forum :applaud:
The transistors are £2 for 10 from ebay, cheaper from online dealers. Either way at this time of year its going to be a few weeks before I get the replacements. If I get 10 then they can all be changed anyway.
Could it be the cold and damp thats caused this problem?
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damp can be a dangerous thing with crt,more than likely i expect yours is just suffering from a one transistor faulty but if you have ever seen a damp crt arc then you would never put a cab inside a garage/shed
the transistor i think is a BF41?
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Believe me if I could have it in the house I would, I have a motorcycle in there too which would also be in the house if the wife would let me, it used to be until we got married.
I have the schematic and it says the transistor is a bc548b and the others are bc558b. Is that not the correct ones then?
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T2 BF859
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Is it the transistors off this board which need replacing?
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sorry mate i gave you the wrong transistor ,for some reason i thought you had said a polo monitor and in fact you have a 9000-forgive me
the transistors you should be looking at are tr7,tr8,tr9 on the main chassis and tr201 on the neck card
the bf859 will replace bf459 just fine-just looks different
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i remember there is something else that can cause your problem,do you have a contrast pot on the chassis or is it a 3 way switch?
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I had the same issue with the blue transistor on one of my MTC9000 chassis, it is indeed a BF459/859 (the 859 has a nice big heat sink :))
Mine were all on the neckboard I do believe (the board in your picture).
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Sorry I havent been back, Ive been busy with xmas etc.
Anyway due to the weather Im hoping to sort this in the next couple of days.
Grantspain I think its a pot but cant be sure, I think Ill take some more pics and let you decide.
Nipedley, you board is like mine? So the transistors which need changing are on this board? Im a complete novice but can handle the soldering iron, Im totally not sure which to change now. The board for the monitor is at the back of the cabinet behind the monitor chassis and looks like a real pig to get at, so Ill be dead chuffed if its the little board in the picture that need the repair.
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could be a pot,the best advice i can give is to swap pot and transistor with another colour
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Im going to update this now as I go.
Just put it into service mode and this was the result.............
So it looks like no red?
Im off now to swap around the 459s..........
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Ive taken out the first transistor and this was the result,,,,,,,,,,,
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Then there was a crackle as I touched the second transisror (the one in the middle of the last pic) so I put it back together and got this.......
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So I removed the one which crackled (one in middle of pic) and got this............
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Theres clearly a picture being generated, but Im unsure why the screen went that red??
Is the advice still to remove the third transistor and swap them around, or should I just buy new ones and replace them all, do you still think its the transistors which are causing the fault??
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can you take a photo of your main monitor board as well.
imo change the red drive transistor and check for bad solder joints
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Just pricing them up from fleabay as maplin dont list them.
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on the first photo you can see a large blue pot on the bottom left,adjust that to see what affect it makes
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Ive removed 201 and 203 from the neck card, should I try it with those removed?
Also what is the transistor value needed for the main monitor board?
Ive sourced the bf459 and according to the schematic its tr7 bc558b tr8 bc548b and tr9 bc548b is that correct??
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just go with the neck transistors for the moment,imo you should put those transistors back in and check
at the moment you seem to be missing gain rather than colour-those pots on the neck card can cause grief so its worth giving them all a tweek
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Ok just got replacement bf459 so going back to put them in now, the pot you spoke of made the screen brighter/darker. I didnt get replacement pots but have twiddled all of them on the neck card when I first got this problem and seem to remember one of them having little effect.
Will report back when these are back in.
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First picture is with red transistor missing, second picture is with red and third is with all three transistors replaced with new ones, and I can confirm the pots next to each colour all have an effect on the picture, the red is definatly working. The blue pot on the mainboard makes the picture brighter/darker. As you can see the problem still exists.
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Ive had a develpoment, I confess to having adjusted the brightness on the the HT transformer and was looking at the picture when there was a sizzling noise and the whole thing went off. I unplugged the unit then plugged it back in to be greeted by a new problem in so much as the sides of the picture have dissapeared!!!
Now what????
Have I done more damage???
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the flyback transformer could be on its way out,a monitor of this age could have a number of problems,i reckon you are in the u.k-whereabouts are you?
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Im in Nottingham.
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bit far for me to help out,i am down in kent-not sure where you should take this,you could end up spending alot on this
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There is a video game place near here so I will give him a ring in the morning.
It was working perfectly before it got cold, dont think its as damp as first thought. On the high score screen, white writing is still displayed where the screen has gone dark. The mainboard looks in good condition, if a little dusty, I keep reading a lot about cap kits, is this not likely to be something along those lines? It depends what you mean by a lot, I really like this machine and would like to get it working again.
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the trouble is with not being in front of the cab its difficult to tell,you have symptons of flyback failure/crt guns weak/no colour gain
if you went along the lines of a cap kit and new flyback and did the work yourself then you are looking at around £30 but if you did all that and it turns out to be the crt you will be well stressed
also important to note that you have an odd crt neck on that tube so it would be difficult to get another type of chassis to fit
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So basically you dont think the unit is worth the cost of repair?
Is the deformed picture the HT flyback?
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the pincushion you are seeing could be down to a bad solder joint/east-west correction diode or possibly the flyback.
the worrying thing is the noise you heard,its either a bad solder joint or the flyback shorting out
this really needs me to be infront of it to help more as i am only guessing
as for rapair costs,well 30 quid is nothing
check for bad solder joints first
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Its going to be another week before I can look at it again, if the flyback has got damp with being in the garage, would it pay to wait for drier weather and hope it gets better?
If I could get it repaired for £30 I would be well happy, it would cost me about £40 in fuel to get to you, and then whatever you would charge to fix it. What would you charge to fix it?
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i reckon the most important thing is to get this cab dry,damp around the anode can cause no end of problems-when the crt is cold it can also display various issues you have
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Thanks you Grantspain, youre a star.
Im going to wait for some good weather now, let it warm up and see what happens. Pity I cant take it on holiday with me next week :lol